Posterior surface of iris
Facies posterior iridis
- Related terms: Posterior surface
Definition
The posterior surface of the iris is directed toward the ciliary processes and lens, in the posterior chamber.
The anterior and posterior surfaces of iris differ in both structure and function. The anterior surface faces the anterior chamber and is irregular and textured, showing features such as the collarette, crypts, and folds. It is mainly composed of stromal tissue and allows the iris to flex and adjust during changes in pupil size. In contrast, the posterior surface faces the posterior chamber and is smooth and uniformly dark due to a double layer of pigmented epithelium. This surface helps absorb light and contains the dilator pupillae muscle, which is responsible for pupil dilation.
References
Standring, S. (Ed.). (2015). Eye (Chapter 42). In Gray's anatomy: The anatomical basis of clinical practice (41st ed., pp. 686-706). Churchill Livingstone.
